Police are investigating whether a carbon monoxide leak led to the deaths of two people in West Rogers Park.

Authorities are investigating whether a carbon monoxide leak caused the deaths of two women in a West Rogers Park apartment building, officials said.

Paramedics were first called about 10:30 a.m. Sunday to the building in the 2500 block of West North Shore Avenue to transport one woman to the hospital, Chicago Fire Department spokeswoman Meg Ahlheim said.

The woman was taken in cardiac arrest to Swedish Covenant Hospital, Ahlheim said.

Fire officials at the scene called for a second ambulance, and another woman was taken to Swedish Covenant as well, Ahlheim said.

Both women died at the hospital.

Rasheeda Akhter, 77, was pronounced dead at 11:14 a.m., according to the Cook County medical examiner's office. The second victim, 18-year-old Zanib Ahmed, died at 9 p.m., according to the medical examiner's office.

Back at the building, fire officials checked the carbon monoxide levels but found no indication of a leak, Ahlheim said.

Paramedics were called back to the scene, however, about 3:45 p.m. for another woman found unresponsive. She was taken to St. Francis Hospital in Evanston in critical condition, Ahlheim said.

Officials checked carbon monoxide levels again, and while the meter readings in residential units did not indicate a leak, officials found a positive reading for a low level of carbon monoxide near a boiler in the basement, Ahlheim said.

Police suspect the deaths were caused by accidental carbon monoxide poisoning, but no official determination will be made until autopsy results are reported, Police News Affairs Officer Amina Greer said.

A spokeswoman for Peoples Gas, Jennifer Block, said representatives from the company were called to the building to assist police and fire officials. She referred further questions to the police and fire departments.